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<head><meta charset="utf-8"><title>Support const parameters in type dependent compiler-team#304 · t-compiler/major changes · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/index.html">t-compiler/major changes</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html">Support const parameters in type dependent compiler-team#304</a></h3>

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<a name="200088874"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/200088874" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#200088874">(Jun 08 2020 at 12:17)</a>:</h4>
<p>A new proposal has been announced <a href="https://github.com/rust-lang/compiler-team/issues/304">#304</a>. It will be brought up at the next meeting.</p>



<a name="200906482"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/200906482" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#200906482">(Jun 15 2020 at 15:36)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="492">@T-compiler</span>: Proposal <a href="https://github.com/rust-lang/compiler-team/issues/304#issuecomment-644209467">#304</a> has been seconded, and will be approved in 10 days if no objections are raised.</p>



<a name="200907466"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/200907466" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#200907466">(Jun 15 2020 at 15:43)</a>:</h4>
<p>oh wow, I didn't know about that going on at all</p>



<a name="200907579"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/200907579" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#200907579">(Jun 15 2020 at 15:44)</a>:</h4>
<p>definitely a sign/anecdotal evidence that MCPs are a good thing</p>



<a name="200907615"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/200907615" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#200907615">(Jun 15 2020 at 15:44)</a>:</h4>
<p>just read up and very <em>very</em> superficially skimmed the PR. This is pretty cool</p>



<a name="202623737"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202623737" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202623737">(Jul 01 2020 at 21:03)</a>:</h4>
<p>This proposal has been accepted: <a href="https://github.com/rust-lang/compiler-team/issues/304">#304</a>.</p>



<a name="202623738"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202623738" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202623738">(Jul 01 2020 at 21:03)</a>:</h4>
<p>This proposal has been accepted: <a href="https://github.com/rust-lang/compiler-team/issues/304">#304</a>.</p>



<a name="202628635"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202628635" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202628635">(Jul 01 2020 at 21:55)</a>:</h4>
<p>unsure why did we get the message twice cc <span class="user-mention" data-user-id="116122">@simulacrum</span></p>



<a name="202628651"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202628651" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202628651">(Jul 01 2020 at 21:55)</a>:</h4>
<p>eh probably a bug, mind filing an issue?</p>



<a name="202628692"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202628692" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202628692">(Jul 01 2020 at 21:55)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span></p>



<a name="202628773"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202628773" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202628773">(Jul 01 2020 at 21:56)</a>:</h4>
<p>just in case, what I'm usually doing is removing the FCP label, adding the accepted label and closing the issue</p>



<a name="202628780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202628780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202628780">(Jul 01 2020 at 21:56)</a>:</h4>
<p>just in case you were expecting something different to happen</p>



<a name="202628946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202628946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202628946">(Jul 01 2020 at 21:58)</a>:</h4>
<p>yeah my guess is we're just not triggering on the right event, we should only check if the accepted label has been added</p>



<a name="202628980"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202628980" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202628980">(Jul 01 2020 at 21:59)</a>:</h4>
<p>but we're probably just triggering on all issue events that touch issues with accepted proposals</p>



<a name="202692507"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202692507" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202692507">(Jul 02 2020 at 14:04)</a>:</h4>
<p><a href="https://github.com/rust-lang/triagebot/issues/666">triagebot#666</a></p>



<a name="202692520"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/202692520" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#202692520">(Jul 02 2020 at 14:04)</a>:</h4>
<p>666 :O</p>



<a name="203254023"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/203254023" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#203254023">(Jul 08 2020 at 10:57)</a>:</h4>
<p>The implementation of this MCP changed slightly in <a href="https://github.com/rust-lang/rust/pull/74113">https://github.com/rust-lang/rust/pull/74113</a>.</p>
<p>While the general idea is still the same, most affected queries are now split into <code>query_name</code> and <code>query_name_of_const_arg</code>, due issues with incremental compilation. What's the correct procedure here? cc <span class="user-mention" data-user-id="116009">@nikomatsakis</span> on how smallish design changes like this should be handled</p>



<a name="203412134"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/203412134" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#203412134">(Jul 09 2020 at 16:58)</a>:</h4>
<p><span class="user-mention" data-user-id="216206">@lcnr</span> I think that's fine, the MCP is an initial proposal</p>



<a name="203412139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Support%20const%20parameters%20in%20type%20dependent%20compiler-team%23304/near/203412139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Support.20const.20parameters.20in.20type.20dependent.20compiler-team.23304.html#203412139">(Jul 09 2020 at 16:58)</a>:</h4>
<p>it can evolve</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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